Polymerization of disilacyclobutane in the presence of a platinum catalyst



United States Patent 4 Claims: c1. 260-2) This invention relates to a new and improved process for the preparation of polymeric organosilicon compounds.

A wide variety of polymeric organosilicon compounds are known and are readily available. Among these materials are the silmethylene polymers, i.e., polymers having a chain of alternating silicon atoms and methylene groups. These polymers have hitherto been prepared by a variety of methods, for example, such as condensation of a lithium derivative of an alkylsilicon compound with a halosilicon compound or a Grignard or Wurtz-Fittig synthesis.

According to the present invention a new and improved process for the production of silmethylene polymers comprises polymerising a substituted disilacylobutane of the general formula BK RIIII wherein the groups R, R", R and R"", which may be the same or different, are monovalent organic or organosilicon groups, halogen or hydrogen atoms, in the presence of a platinum catalyst as hereinafter defined.

By the phrase a platinum catalyst as used herein we mean a simple or complex salt of a platinnum metal, for example, such as platinous bromide, platinous chloride, chloroplatinic acid, dil-chlorodichlorobis(cyclohexane) diplatinum (ll), di- -chloro-dichlorobis (decene) diplati num (l1), bis(diethylsulphide)dichloroplatinum (11), di methylbis(triphenylphosphine)platinum (1 1), bis(tripropylarsine dichloroplatinum 1 l methylbis (trimethylphosphine bromoplatinum 11), bis (tripropylphosphine) dichloroplatinum (11), sodium chloroplatinate, di- -chlorodichloro-bis(tributylphosphine) diplatinum (1 l palladons bromide, palladous chloride, bis(triphenylphosphine) dichloropalladium (l1), di- -chloro-dichlorobis(triethylphosphine)dipalladium (11), ruthenium tiichloride, iridium trichloricle and iridium hydroxide. Catalysts which can readily be dissolved or dispersed in the disilacyclobutane are normally preferred. Catalysts in which the platinum metal is platinum are also in general preferred. It is further preferred that the catalyst be a complex of an olefin and for many purposes the preferred olefin is cyclohexene.

The groups R, R", R' and R"" in the silacylobutane may be alkyl, aryl, aralkyl, alkoxy, aryloxy, siloxy or silalkylene groups or halogen or hydrogen atoms. Suitable groups include, for example, methyl, ethyl, benzyl, phenyl, trimethylsiloxy and trimethylsilylmethyl groups.

The catalyst may be present in widely varying proportions, for example, from less than 0.001 to 0.1 part by weight or more of platinum metal per part of the substituted disilacycyclobutane. It is, however, in general preferred to use the catalysts in amounts of the order of from 0.002 to 0.02 part of metal per part of the disilacycyclobutane.

The polymerisation may be carried out over a wide range of temperature, for example, from to 200 C. It is, however, in general satisfactory and is preferred to operate at temperatures of the order of 50 to 120 C. The reaction may also be carried out over a wide range Patented Dec. 20, 1966 of pressures. It is, however, normally preferred to operate at atmospheric pressure.

If desired the reaction may be carried out in the presence of a solvent, for example, such as hexane, benzene, toluene or tetrahydrofuran. If a solvent is used it may be present in amounts up to, for example, parts by weight per 100 parts by weight of the disilacyclobutane.

If desired the catalyst may be separated from the resulting polymer. One method of achieving this is by adding active charcoal to a solution of the polymer in a solvent, filtering the mixture and distilling off the solvent.

The products of our invention can be used in a wide variety of applications, for example, as hydraulic fluids, as lubricants and as bases for elastomers.

Our invention is further illustrated by the following examples in which all parts are by weight.

Example 1 1 part of di- -chloro-dichlorobis(cyclohexane)diplatinum (11) was added to 500 parts of 1,1,3,3-tetramethyl- 1,3-disilacyclobutane and the mixture heated at 70 C. for 2 minutes. A vigorous reaction ensued as a result of which there was obtained a dark coloured polymeric material. This was dissolved in 1000 parts of benzene and the solution heated under reflux with 10 parts of de colourising charcoal for 5 minutes. The solution was then filtered and the solvent removed by distillation whereby there was obtained 450 parts of a viscous colourless material of viscosity 100 cs. at 20 C., refractive index 1.465 at 18 C., S.G. 0.8 and which was insoluble in water and soluble in organic solvents such as benzene. This material was of value as a lubricant, a hydraulic fluid, an additive for silicone greases, a constituent of water repellent compositions and as an insulator in electrical applications.

Example 2 1 part of chloroplatinic acid was added to 500 parts of l,1,3,3-tetramethyl-l,3-disilacyclobutane and the mixture heated at 70 C. for 2 minutes. There was thus obtained 480 parts of a syrupy liquid of viscosity 300 cs. at 20 C.

Example 3 1 part of bis(diethylsulphide)dichloroplatinum (11) was added to 500 parts of l,1,3,3-tetramethyl-1,3-disilacyclobutane and the mixture heated at 70 C. for 2 minutes. There was thus obtained 490 parts of a liquid of viscosity 100 cs. at 20 C. This material was of value as an electrical insulator and as a lubricant.

Example 4 1 part of =di- -chloro-dichlorobis(cyclohexene)diplatinum (1 1) and 500 parts of 1,3-diet.hoxy-1.3-dirnethyl-1,3- 'disilacyclobutane were warmed to 70 C. for 5 minutes, allowed to cool and maintained at 20 C. for 2 days. Thereafter the mixture was warmed to 60 C. at 0.02 mm. Hg pressure, whereby there were obtained 495 parts of a polymeric gum, the LR. spectra of which showed the disappearance of the band at 10.55

Example 5 1 part of di- -chloro-dichlorobis(cyclohexene)diplatinum (l1) and 500 parts of l,3-dimethyl-1,3-diphenyl-1,3- disilacyclobutane were reacted in the manner described in Example 4. There were thus obtained 475 parts of a clear yellow/brown viscous liquid.

Example 6 2 parts of di ,u. chloro-dichlorobis (decene)diplatinum (11), 500 parts of 1,1,3,3-tetrametl1yl-1,3-disilacyclobutame and 500 parts of l,3-diethoxyl-l,3-dirnethyl, 1,3-di silacyclobutane were heated to 60 C. There was an immediate vigorous exothermic reaction, .-giving a product 3 consisting of 980 parts of a viscous liquid. The LR. spect-ra showed strong bands at 8.6 and 9.05 1 attributable to Si-OEt groups.

Exampfies 7 to 20 500 parts of 1,1,3,3-rtetramethyl-1,3-disilacyclobutane were heated with 1 part of the specified catalysts in the manner described in the following table:

Heating Example Catalyst Product Time Temp. (min) C.)

7 Platinous bromide 2- 70 Gum.

8 Dimethylbis(triphenyl- 30 120 Do.

ptiosphinemlatinum 9 Bis(tripropylarsine) 60 120 Viscous diohloroplatinum (11). fluid.

10 Methylbis(trimethy1- 180 120 Do.

phosphine)bromoplatinum (11).

11 Bis(tripropylphosphine) 30 120 Gum.

dichloroplatinum (11).

12 Sodium ehloroplatinate- 120 120 vilscouls 1 iqui 13 Di-Y- -chloro-dichloro- 80 Very viscous bis(tributyl phosphine) liquid. diplatinuln (11).

14 Palladous bromide 5 120 Gum.

15 Palladous chloride. 5 120 Do.

16 Bis(triphenylphosphine) 60 120 Powdery dichloropalladium (l1). gum.

17 Di- -chlorodichloro-bis 120 120 Do.

(trimethylphosphine) dipalladium (11).

18 Ruthenium trichloride 25 110 Clear gum,

l9 Iridium hydroxide 120 Clear viscous liquid.

wherein the groups R, R", .R' and R", which maybe the same or different, are selected from the group consisting of lower alkyl, lower alkoxy and phenyl radicals,

and halogen and hydrogen atoms, in the presence of simple and complex salts of a platinum metal catalyst selected from the group consisting of platino-us bromide, p-latinous chloride, chloroplatinic acid,

di- -chl'orodichlorobis (cyclohexene) diplatinum 1 1) d'i- -ehloro-dichlorobis (decene) diplatinum- 11),

bis diethylsulphi-de) dichloroplatinum 1 1 dimethy'lbis(triphenylphosphine) platinum (1 1), bis(tripropyl=arsine) dichloroplatinum 11), methylbis(trimethylphosphine) bromoplatinum (1 1), bis triprop'ylp-hosphine dichloroplatinum l 1 sodium chloropla-tinate, di- -chloao-dichlorobis(trihutyl hosphine)diplatinum palladous bromide, V paill-adous chloride, bis (triphenylpho sphine) dichloropalladium 1 1 di-u-chlorodichlorobis(triethylphosphine)dipalladium ruthenium trichloride, iridium trichloride and iridium hydroxide.

2. A process according to claim 1 wherein R, R", R', R" are selected fir om the group consisting of methyl, phenyl, and ethoxy groups.

3. A process according to claim 1 wherein the catalyst is used in an amount of from 0.001 to 0.1 part by Weight of platinum metal per part of disilacyclobutane.

4. A process according to claim 1 where the polymerisation is carried out at a temperature of irom 10' to 200 C.

References Cited by the Examiner UNITED STATES PATENTS 2,381,000 8/1945 Patnode et a1 260448.2 2,483,972 10/1949 Goodwin 26-0-4481 2,590,937 4/1952 Clark 260448.2 2,850,514 9/ 1958 Knoth 260M482 3,178,392 4/1965 Kriner 260-4482 LEON I. BERCOVITZ, Primary Examiner.

DONALD E. CZAJA, Examiner.

M. I. MARQUIS, Assistant Examiner. 

1. A PROCESS FOR THE PRODUCTION OF SILMETHYLENE POLYMERS COMPRISING POLYMERISING A SUBSTITUTED DISILACYCLOBUTANE OF THE GENERAL FORMULA 